Thread-milling machine.



N. A G En 0 M .P. & N rr. D L 0 H P. am

THREAD MILLING MACHINE. APPLICATION FILED MAY 2s. I9I5.

Patented Fab. 13, 1917.

3 SHEETS-SHEET I www@ l I sgi A. P. HOLDEN @L P.l MRGAN. THREAD MILLINGMACHINE. APPLICATION FILED MAY 29, 1915.

gl QSGL Patentd Feb. 13, 1917.

f Z f@ I' Zd C' A P HOLDEN&P MOR N. THREAD MILLING MACHINE. APPLICATIONFILED MAY29 9|5 31,215,89@ Patented Feb. 13, 1917.

3 SHEETS-SHEET 3 f ras n ernten.

ARTHUR PEART HOLDEN .AND PHILIP MORGAN, OF TORONTO, ONTARIO, CANAD.

THREAD-MILLING lMACHINE.

Specification of Letters Patent.

` Patented Feb. I3, i917.

Application led May 29, 1915. Serial No. 31,307.

To all whom t may concern.'

Be it known that we, ARTHUR PEART HOLDEN and PHILIr' MORGAN, both of thecity of Toronto, in the county of York and Province of Ontario, Dominionof Canada, have invented certain new and useful Improvements inThread-Milling Machines;

' and we hereby declare that the following is a full, clear, and exactdescription of the same. y

In the manufacture of high explosive shells, it isnecessary to bore ablind hole centrally in the base of the shell and thread it for thereinforcing plug which receives the force of the firing charge, novariation being permitted in the'diameter of the hole,

' or the perfection of the thread.

The present machine has been particularly designed for automatically andcorrectly centering the partly-finished shell to the axis of therevolution of the chuck -which operates to 'simultaneously feed the workin an axial direction during its revolution and determine the pitch ofthe thread while the milling operation is being performed, therevolution of the chuck on the completion of the thread beingautomatically arrested, and for perfectly milling -a completed thread tothe bottom of a blind hole of this character, so that the threaded stemof the reinforcing plug will completely` in section, showing the feedring; and Y Fig. YI, is a longitudinal lsection of a high explosiveshell showing the reinforcing plug fitted tothe base.

Like characters of reference refer to like parts throughout thespecification and drawings.

In the manufacture of shell projectiles,

each shell a, which is drilled and turned to the required size andshape, is provided in the ma:-

Fig. V, is a perspective detail view, partly j the .base a witha. blindhole a, having a perfect thread a3 from the inner to the outer end ofthe hole. This threaded hole must be of uniform diameter throughout itslength to form a tight it`with the threaded shank b of the reinforcingplug b', so that the gas' from the firing charge cannot penetratebetween the wall of the hole and the shank.

Rapidity and accuracy are two important factors in the manufacture ofthis class of article, particularly during war periods, in order tomaintain the supply of high-grade ammunition for the requirements at thefront.

In order to successfully carry on the manufacture of this type of shell,the milling machine is provided with a substantiallycylindrical workholder or chuck c having an axial bore c therethrough of substantiallycorresponding shape and dimensions to the external shape and dimensionsof the shell a, so that when the partly-finished shell a is insertedinto the bore of the cylindrical chuck, it will be automatically andaccurately centered.

As shown in Fig. I, the base of the shell a is opposed to the millingtool d, and that part c of the bore c engaging the base a of the shellserves as a positive stop to correctly locate or position the shellwithin the.

work holder and converges to form a clamping member for engaging thatend of the work. i

The opposite end 03 of the axial bore c to the converging end c isthreaded to receive a hollow clamping member e, the inner end of thebore evof the clamping member e being of a correspondingshape to the.nose L4-'of the shell a, and the outer surface ofw the clamping member ebeing threaded to-engage with the threads of the end c3 so that when theclamping member e is tightly screwed into the bore of the cylindricalchuck c, it will bind against the nose Bf the shell a and force thebasenof the shell against the converging part .0 "and lock the shellwithin the chuck, which then will unitedly revolve with the chuck.-

The chuck c is journaled in three bearings f, ff, f supported by theframe g, and

bearings f,.f is threaded as shown at h, of corresponding pitch to thethread a3' to be milled`in the blind. hole af in the base of the shella.

"the outer surface of the chuck between the Encircling the chuck cbetween the bearings f, f', is a divided feed ring z' having itsl borethreaded to correspond with and engage the thread h on the outer surfaceof the chuck c, the bearings f, f preventing the lateral movement of thefeed ring. As shown in Fig. VV, the feed ring z' consists of two membersz",., pivoted at one side to the flanges f4 of the bearings f, f', sothat they can be swung into open or closed relation with the cylindricalchuck o for the `purpose of disengaging the threaded surface 3 of thebore of the feed ring from the threaded surface Z1. of the cylindricalchuck, when it is desired to quickly move the chuck in the direction ofthe milling tool d.

Pivoted to the free end of the member z" is a bolt which, in itsoperative position, enters between the forks j ofthe member 2'. The boltj, as shown in Fig. V, is provided with a nut lo to engage the forks jfor the purpose of drawing the free ends of the members z", d togetherand bringing by a bolt m passing through an elongated thethreadedsurface 3 of the bore of the feed ring into engagement with thethreads It of the cylindrical chuck. Splined on the cylindrical chuck c,between the bearings f, f, is a Worm wheel Z partly covered by a guardcasing g, and cut in the bore of the worm wheel and the perimeter of thechuck c, are keyways for the keys a which, while causing the unitedrevolution of the worm wheel and chuck, permit the chuck to slideaxially through the worm wheel, the lateral movement of the worm wheelbeing prevented by the bearings f, f, which are located close to itsside faces. The worm wheel Z meshes with a worm Z mounted on a shaft Z3,provided with a pulley Z, and journaled near one end in a rockingbearing m, and at the other end in a movable bearing m slidablyrconnected to the frame g slot m8 in the bearing.

Bolted to the frame g is an arm 0, to which is fulcrumed a lever ohavingN a shoulder o engaging a li-p p on the movable bearing m tosupport the bearing when holding the Worm Z in mesh with the worm wheelZ, and on the end of the chuck c is a collar p having a liange pengaging the lever o.

The starting position of the partslis that shown in Figs. I and II, thechuck c in this position being moved lengthwise to its limit of movementin the direction indicated by arrow, its further movement in thatdirection being arrested by the flange p on the collar p abuttingagainst the bearing f.

The flanged collar p, p is provided with a stop pin q and the bearing 71s provided with a stop pin g, the chuck when coming to the startingposition being turned in the direction indicated by arrow 1n Fig.

lip, the movable bearing ve of the ore of the chuck, the shell thenbeing correctly centered and tightly vclamped within the cylindricalchuck.

The milling tool ZZ, fixed on a Shaft al mounted in bearings cZ movablelength- Wise and laterally of the frame g, is then shifted to commencemilling at the inner end of the blind hole a, motion being transmittedthrough the pulley Z3 tothe shaft d and milling tool al.

When the milling tool aZ has been corhtly against the converging partrectly positioned, the worm Z is moved into mesh with the Worm wheel Zand the leve o is moved into position to support the movable bearing mfor the worm and main'- tain the worm in mesh with the worm wheel whilethe milling operation is being performed.

When the Worm is brought into mesh with the worm wheel, the revolutionof the chuck and shell starts, and the milling tool commences to millthe thread in theblind hole a.

During the revolution ofthe chuck, the meshing of the threaded surfacel1. of the chuck with the threaded surface 3 of the feed ring e' feedsthe chuck in a direction away from the milling tool and` not only causesthe milling of the thread in the blind hole a corresponding inthe pitchto that of the threaded surfaces l1., 3, but also causes the pin gtoclear the pin Q.

During this feed of the chuck c, the ange p gradually works the lever 0outward, as

and ultimately disengages the shoulder o form the lip p. v

When the shoulder is disengaged from the lm. drops into the positionindicated in dotted lines in Figs. I and II, releasing the worm frommesh with the worm wheel and stopping the motion of the chuck, this stopmotion being timed to correspond with the completion of the milling ofthe thread in the blind hole. The clamping member e is then'removed andthe threaded shell is withdrawn from the chuck, a freshA shell isinserted in the chuck, and the clamping member is replaced. To quicklymove the chuck-to lits limit of motion in the direction of the millintool al, the nut lc is slackened on the bo t y', the

.. members z", z' of the feed ring are opened to disengage the threadedsurface 3 from the inner end of the blind hole and the worm is movedinto mesh with the worm wheel to repeat'the milling operation.

By means of this construction, a perfectlyformed thread can be rapidlymilled in the blind hole, and without supervision, it being onlynecessary for the operator to place the work in and remove it from themachine.

Having thus fully described the nature of our invention, what we claimas new and desire to secure by Letters Patent, is:-- y

l. A'thread milling machine comprising a set of bearings, anaxially-movable cylindrical work holder journaled therein having itsouter surface threaded, threaded means engaging with the threadedsurface of the work holder for causing its axial movement, a worm wheelmounted on the work holder, means for slidably securing the work holderto the worm wheel, a worm meshing with the worm wheel, journaled at oneend in a rockable bearing and at the other in a movable bearing, and apivoted support for the movable bearing displaced therefrom by the chuckwhen it has reached the limitV of movement in an axial direction.

2. A thread milling machine comprising a set of bearings, a cylindricalwork holder journaled therein having its outer surface threaded, a clamphaving its inner surface threaded to engage with the threaded surfaceofthe work holder, said clamp consisting of two clamping members locatedbe? tween two of the bearings, and aclamping bolt and nut closing themtogether, a' worm wheel mounted `on `the work holder,'a key entered in akeyway in the worm wheel and work holder for slidably securing the workholder to the worm wheel, a worm meshing with the worm wheel, journaledat one end in a rockable bearing and at the other in a movable bearing,and a pivoted support for the ymovable bearing displaced therefrom bythe chuck when it has reached its limit of movement inan axialdirection.

an axially-movable hollow rotatable, work holder havin ward one enclamping means within the bore to hold the work therein, a gear wheel towhich the work holder is splined so that it is rotated by the wormwheel, but is free to move axially through it, the outer surface of thework holder having a feed thread thereon, and means engaging with thefeed thread to cause the axial movement ofthe work holder duringitsrotation.

an axial bore tapering `to\v 4. A thread milling machine comprising ahollow rotatable work holder having an axial boretapering toward oneend, a clamping nut adjustable in the other end of said bore,cooperating with the tapering end to correctly position and securely`hold the work within said holder, a bearing in which the work. isjournaledand through which it is axiallyrmovable, a gear wheel splinedto the work holder so that as it is rotated the work holder will moveaxially through it, a feed thread on the external surface of the workholder, and means engaging with the feed thread to cause the axialmovement of the work holder as it rotates.

5. A- thread milling machine comprising an axially-movable hollowrotatable work holder having an axial bore, clamping means to hold thework there-ima worm wheel splined to the work holder so that the workholder is rotated by it and is free to moveaxially through it, a wormmeshing with the worm wheel, a movable bearing for the worm, and apivoted support for the movable bearing, displaced therefrom by the workholder when it has reached the limit of movement in an axial direction.

6. A thread milling machine comprising a bearing, an axially-movablecylindrical work holder journaled therein having a feed thread on itsouter surface, threaded means engagin with the feed thread of the workholder or causing its axial "movement, a worm wheel mounted on fthe workholder, means for slidably securing the work-holder to the worm wheel, a.form meshing with the worin-wheel journaled at one endin a movablebearing, and a pivoted supportfor the movable bearing displacedtherefrom by the Work holder when it has reached the limit of movementin an axial direction.

. 7. A thread milling machine comprising Ia bearing, a cylindrical workholder journaled in andaxially movable through. the bearing, a wormwheel splined to the work holder so that the work holder is'free to moveaxially through it, a worm meshing With the worm wheel to Cause therotation of the work holder, means for effecting the movement lofthework holder in an axial direction, and means for dlsengaging 'the wormfrom the worm wheel when the work J holder has reached its limit ofaxial move- 3. A thread milling machine comprising 4move axially throughit, a worm meshing with the worm wheel, a movable bearing in which oneend of the worm is journaled, and

a pivoted support for the movable bearing,

displaced therefrom by the work holder loo;

v when it has reached its limit of movement in an axial direction.

9. In a thread milling machine, the combination of a bearing, anaxially-movable Work holder rotatable therein, a Worm Wheel 'splined tothe Work holder so that the Work holder is axially movable through it, aWorm meshing with the Worm Wheel, means causing the axial feed movementof the Work holder, and vmeans holding the Worm in mesh With the WormWheel displaced by th'e Work holder When it has reached the limit of itsaxial movement releasing the Worm from the Worm Wheel.

10. In a thread milling machine, the combination of a bearing, anaxially-movable Work holder rotatable therein, a Worm Wheel splined onthe Work holder so that the Work holder is axially movable through it,means for holding the Worm Wheel' against axial movement, a Worm meshingWith the Worm Wheel, means causing the axial feed movel ment of the Workholder, and means holding the Worm in mesh With the Worm Wheel displacedby the Work holder When it has reached the limit of its axial movementreleasing the vvorm from the Worm Wheel.

11. In a thread milling machine, an axially-movable cylindrical Workholder, means causing the axial feed movement of the Work holder, a WormWheel splined on the Work holder so'that the Work holder is axiallymovable through it, a Worm meshing With the Worm Wheel, a movablebearing in which the Worm is journaled, and a support for the movablebearing holding the Worm in mesh With the Worm Wheel displaced by theWork holder When it has reached the limit of its axial movement re-.bination of a bearing, an axially-movabley cyllndrical Work holderrotatable therein, a.

leasing the Worm from the Worm Wheel.

12. In a thread milling machine, the4 com- Worm Wheel splined on theWork holder so that the Work holder is axially movable through it, meanspreventing the movement of the Worm Wheel in an axial direction, a Wormmeshing With the Worm Wheel, a movable bearing in Which the Worm isjournaled, and means holding the movable bearing to maintain the Worminmesh With the Worm Wheel displaced by the Work holder when it hasreached the limit of its axial movement releasing the Worm from the WormWheel.

13. In a thread milling machine, the combination of a bearing, anaxially-movable` Work holder rotatable therein, .means for causing theaxial feed movement of the Work holder, a Worm Wheel splined'on the Workholder so that the Work holder is axially movable through it, meanspreventing the movement -of the Worm Wheel in an axial direction, a Wormmeshing with the worm Wheel, a movable bearing in Which the Worm isjournaled, and a .pivoted arm, supporting the movable bearing holdingthe Worm in mesh with the Worm Wheel displaced by `With the Worm Wheeldisplaced'by the Work holder when it has reached the limit of its axialmovement releasing vthe Worm from mesh with the Worm Wheel.

Toronto, May 10th, 1915. Y

, ARTHUR PEART HOLDEN.

PHILIP MORGAN. i

